The present invention is a continuing application of the eight-stroke internal combustion engine, which was filed as U.S. Pat. No. 6,918,358 (application Ser. No. 10/619,147), and the engine of this type can also be abbreviated as the eight-stroke engine.
The fuel efficiency of the eight-stroke engine is relatively higher than the conventional four-stroke engine (over 35% for gasoline type eight-stroke engine and 45% for diesel type eight-stroke engine) under the condition that the engine load remains within the designated load condition.
However, unlike conventional engines, the eight-stroke engine requires to adjust the initiation timing of the injection-process (the process to inject a flow of high-density-air into the master cylinder) as the load changes, otherwise, the power-to-weight ratio will significantly decrease due to the compression energy loss and the heat loss during the slave-compression-process in the heavy load condition.
Therefore the main objective of the present invention is to provide an improved eight-stroke engine capable of adjusting the initiation timing and regulating the maximum compression pressure according to the engine load condition.